Aromatic lubricants and their method of preparation



United States Patent 3,173,965 AROMATIC LUBRICANTS AND THEIR METHOD OF PREPARATION James J. Pappas, Elizabeth, and Fred H. Kant, Crant'ord,

.J., assignors to Esso Research and Engineering Company, a corporation of Delaware No Drawing. Filed June 28, 1961, Ser. No. 120,176 10 Claims. (Cl. 260667) This invention relates to alkylated benzenes suitable for use as fluid lubricants, to their preparation and to their use.

Three of the most important properties of fluid lubricants, such as automotive crankcase lubricants, are viscosity, viscosity index, and pour point. For many lubricants, especially those used for internal combustion engines, the minimum desirable specifications are that the viscosity at 210 F. should be between 32 and 280 S.U.S.s, they should have a pour point below about 35 F., and a viscosity index (Dean-Davis) above about 90. It has been customary in the art to modify lubricating oils with additives to meet or improve such specifications. The present invention resides in the techniques for preparing compositions which, even without such additives, have V.I., and pour point properties which are much better than even highly refined mineral oils.

The compositions of this invention can be used to lubricate internal combustion engines. They can also be used as special lubricants, e.g. transmission oils, refrigerator oils, instrument oils, jet lubricants and the like.

The compositions of the invention are prepared from benzene or alkylated benzenes. The preferred compositions of this invention are dialkylated benzenes, i.e. paradialkylated benzenes. When dialkylated benzenes are desired, the alkylation can be accomplished by simultaneously reacting all of the alkyl reactants with benzene, but preferably it is accomplished by first completely reacting one alkyl reactant with benzene and then reacting the resulting reaction mixture with the other alkyl reactant. The preferred technique is to first alkylate benzene with one alkyl reactant, then separate the resultant monoalkylated benzene from the reaction mixture and alkylate it with the other alkyl reactant. The yields of desired dialkylated product are considerably higher when using the preferred technique. It monoalkylated benzenes are available, these can be used as a starting material. Consequently, only a single alkylation is necessary to achieve the desired dialkylated benzene product. The alkyl substituents can have from 4 to 21, e.g. 5 to 18 carbon atoms. When the monoalkylated benzene is desired, the alkyl substituent should have a minimum of carbon atoms.

Alkylation as used herein means a process for introducing alkyl substituents onto a benzene residue in which the linkage is through the oz-carbon atom of the alkyl substituent. It is preferably accomplished by any of the variations in the well-known Friedel-Crafts reaction. Thus, alkylation may be accomplished in the presence of a suitable inorganic halide Friedel-Crafts catalyst, such as Alfllg, AlBrg, FeCl SnCl ZIICIZ, HF, H2804, P 0 and H PO a-Olefins, monohydroxylated or monoice halogenated parafi'ins can be employed in the Friedel- Crafts reaction. Preferably the olefins and paratfins are normal when products having a high viscosity index are desired. These materials, when reacted with benzene in the Friedel-Crafts reaction, produce a material repre sented by:

wherein Z is a C to C e.g. a C to C alkyl radical, and Z is selected from the group consisting of H and C to C e.g. a C to C alkyl radical. Z and Z are preferably para to each other. The preferred Friedel- Crafts reaction of this invention is carried out with an alpha olefin reactant and aluminum chloride catalyst. Preferably, the aluminum chloride (AlCl is anhydrous and the reaction is preferably carried out in an anhydrous hydrogen chloride atmosphere. The hydrogen chloride atmosphere tends to rapidly drive the reaction to completion, but its use is not critical. The reaction can be carried out at any convenient temperature. However, temperatures between 30 and 100 F., e.g. 50 to F., are preferred. The mole ratio of aromatic to any of the alkyl reactants can range from 0.111 to 10:1, e.g. 1:1 to 3:1. The molar proportion of catalyst is 0.01 to 0.20, e.g. 0.03 to 0.15, moles per mole of olefin reactant.

After the reaction is complete, the hydrocarbon layer of the reaction mixture is Washed and then neutralized with a suitable neutralizing agent such as an aqueous sodium bicarbonate solution. Any unreacted benzene and alkyl reactant are removed by distillation and the alkylated product is fractionated to give the desired product. Usually the desired product is that which distills off above 700 F. at atmospheric pressure. That fraction distilling between 700 to 950 F. at atmospheric pressure is most desirable.

One of the outstanding features of the present invention is that alkyl substituents having certain chain lengths and certain degrees of branchiness can be selected to influence, predictably, a given desired property of the resulting product. Thus, by proper selection of the alkyl substituents, a final product having pour points ranging from to +15 F., V.l.s from to 145, e.g. to 145, and viscosities from 35 to 50 S.U.S. at 210 F. can be prepared.

Polyalkylated aromatics, monoalkylated aromatics, and dialkylated aromatics in the meta or ortho positions tend to have the least desirable lubricating properties. When branched olefin reactants are employed, the tendency of the resulting product is to have low pour points but also relatively low V.i.s. Also, products having better pour point properties are those having two alkyl substituents having a total of at least 9 carbon atoms for both constituents. When the alkyl substituents have approximately equal numbers of carbon atoms but not less than about 8 per alkyl reactant, the tendency of the final product is 3 to exhibit extremely low pour points and also relatively low V.I.s. When one .of the alkyl reactants has substantially more carbon atoms than the other, the tendency is to obtain higher V.I.s and also somewhat higher pour F. at atmospheric pressure, the anhydrous aluminum chloride was added and stirring commenced. Hydrogen chloride gas was'then squeezed from the gas bag into the reaction mixture. Olefin was gradually added dropwise points. This tendency is more pronounced when the 5 over a period of one hour while the temperature of the minimum number of carbon atoms per alkyl substitutent reaction mass was held between 55 F. and 59 F. by is about and there is a difference of from about 3 to 8 using an ice bath. After all the olefin hadbeen added carbon atoms in the length of the longer alkyl reactant to the reaction mixture, the mixture was stirred for an as compared with the length of the shorter alkyl reactant. additional 10 to minutes. The reaction mixture was When the number of carbon atoms in the shorter alkyl re- 10 then transferred to a separatory funnel where sludge was actant ranges from 6 to 9 and there are from about 3 to allowed to settle and removed. The resultant hydrocar- 15 more carbon atoms in the longer alkyl reactant, the hon layer was washed several times with water, followed tendency is for the final product to have a relatively high by washing with a 5 wt. percent aqueous sodium bicarbon- V.I. and a high pour point, the trend increasing as the ate solution and followed with additional water washing difference in the number of carbon atoms in each alkyl 15 until neutral. The 'unreacted benzene and olefin were rereactant approaches a maximum. As the number of carmoved by distillation. The monoalkylated benzene prodbon atoms in each of the alkyl reactants approaches the uct was distilled. A second alkylation was carried out by point where there will be the same number of carbon following the same general procedure and using the monatoms in each alkyl reactant, but at least 10 per alkyl reolakylate'd product just obtained in place of benzene. aotant, the V1. tends todecrease while the pour point The dialkylated benzene was fractionated at a pressure of also tends to decrease. A further advantage of this infrom 0.1 to 0.2 mm. of mercury to give a product boiling vention is that compositions having very satisfactory lubriabove 750 F. at atmospheric pressure. The product eating properties can be prepared from somewhat impure boiling above 750 F. at atmospheric pressure was furcommercial refinery streams as well as from pure reacther fractionated at a pressure of from 0.1 to 0.2 mm. of tants. mercury to produce a final product boiling between 750 The alkylalted benzenes of this invention can be further to 950 F. at atmospheric pressure. treated by hydrogenation if desired. By hydrogenating In several of the compositions, the olefins used were the alkylated benzenes it is possible to improve their obtained from cracked petrolatum and cracked wax. stability to oxidation without appreciably affecting their These olefins were obtained by fractionating the gross other properties] Thus, there is virtually no change in product from steam cracking of petrolatum and/or wax V1. and pour point and only a slight increase in viscosity derived from North Louisiana crude. The olefin cuts after hydrogenation. Any conventional hydrogenation represent the C -C fractions of. the steam cracked prodtechnique can be used. A preferred hydrogenation is caruct having a boiling range of from 130 to 690 F. at ried out with a Harshaw Nickel on Keiselguhr catalyst atmospheric pressure. at about 400 F. and at about 1000 psi. above atmos- For each run, two compositions were obtained. These pheric. were designated by a letter and a letter prime. The two The compositions of this invention can be used, per se, compositions represent (1) the product boiling above as lubricants. They can also, if desired, be used with 750 F., and (2) the product boiling between 750 to conventional additives such as neutralized phosphosul- 950 F. furized hydrocarbon detergents, zinc dialkyl dithiophos- 40 EXAMPLE II hate extreme pressure agents, trialkyl phenol antioxidants, and the like. The compositions of this invention can also A Semis of Compositions Was P p using P be thickened to a grease consistency with conventional cedllre of Example 1 except that there Was j one ky thickeners such as lithium l2-hydroxy stearate and cali P- TWO Products were evaluated for each i ap-calciufn t t 1 These were the product boiling above 700 F. and the It will be apparent to one skilled in the art, from the profillct boiling bfitween to ThiTtY'SiX above and from the following examples, how to prepare P f Wfire P ep n i manner and labelled as compositions having the particular property desired. der1bed for amp The lie-T056116 extract U d in this example was obtained in a 20% yield from a whole EXAMPLE I kerosene fraction by selective extraction with S0 The A series of compositions was prepared by the followextract consisted of approximately 25% saturates and ing procedure. Benzene was placed in a four-necked 75% aromatics which were predominantly C -C polyflask equipped with stirrer, thermometer, and addition alkylated benzenes. funnel to which was attached a gas bag containing anhy- The details relative to .the compositions of Examples I drous hydrogen chloride. The benzene was cooled to 55 and Ii are summarized in the following tables.

Table I] DIALKYLATION 0F BENZENE First Alkylation Composition I .A/A B/B o/o' DID i E/E' l F/F I G/G I H/H Reaetants:

Benzene, gms 624 624 624 322 624 024 624 624 Olefin: V

Type..- I C0 C5 C0 C12 C0-C9 Cut-C15 Cur-C15 lo- 15 Purity P e 2 racked Wax Amou 336 449 449 g 340 420 700 700 700 A1013, gms. 53. 2 s3. 2 53 2 27. 6 26. 6 20. 6 26.6 26. 0 gl gggtii on Tem F 55-59 55-59 55-59 55-59 55-59 55-59 55-59 55-59 Reaction Time, Min. 70 70 75 75 75 75 fii i ifiifii f 400-420 470-490 470-490 580-600 375-550 500-700 500-700 500-700 Amount, gm5 432 547 529 224 31s 7 475 433 475 1 An H01 blanket was over the reaction mixture. 2 Contains 86% monoolefins, 8% diolefins, 6% aromatms.

Table 1'2 DIALKYLATION OF BENZENE Second Alkyiation Composition A/A BIB C/G' D/D E/E' F/F' GIG H/H Reactants:

gilorglalkylated Benzene, gms 200.0 200. 240. 0 220. 0 299.0 474. 432. 4 475. O

G18 C C15 C12 Ola-C2: GIG-C15 Cm Cit-C21 Pure Pure Pure Pure 155. 5 1.33. 2 160. 0 '76. O 205. 9 105. 0 215. 5 244. 0 8.2 7.0 16. 8 6.0 10.9 12. 5 11. 4 12.6 Reaction Temp, F 55-59 55-59 55-59 55-59 55-59 55-59 55-59 55-59 Reaction Time, Min 70 70 70 75 75 75 75 76 Products:

HG after Wash, grns 308. 5 277. 0 319. 5 235. 6 405. 7 530. 5 597. 5 478. 0 Sludge, gms 7. 5 12. 0 59. 0 14. 5 42. 3 28.6 9. 0 52. 0 Dist. of P10d., gms.:

750 F 123. 5 90. 1 177. 5 105.7 160. 2 234. 6 211. 5 194. 0 750-950 F 144. 7 155. 1 127. 2 110. 6 194. 0 236. 8 314. 2 146. 8 950 F 40. 3 31. 8 14. 8 19. 3 51. 5 59. 2 71. 8 137. 2 Insp. of 750 1'. Prod;

Visc. at 210 F., SSU 44. 7 43.3 47. 2 42. 5 48. 4 47. 3 47. 6 56. 4 VI 132 129 114 120 115 120 127 120 Pour Point, F +25 15 -65 +5 15 Insp. 0i 750950 F. Prod;

Vise. at 210 F., SSU 41. 6 43.0 45. 2 40.9 43.4 41. 6 46.0 47. 4 V1 127 126 109 113 112 98 125 118 Pour Point, F +15 0 -30 25 75 9 30 1 Cracked Petrolatum. 2 Cracked Wax. An H01 blanklet was over the reaction mixture.

Table I-3 MONOALKYLATION OF AROMATICS Composition 111 IN K/K L/L M/M N/N 0/0 P/P Q/Q Reactants:

Aromatic Compound:

ype n-Butyibenzene Toluen Benzene p-Xylone Mestylone Amount, gms 134. 2 268. 4 I 247. 1 184. 2 268. 4 156.2 212. 3 240. 4 358. 0 1-Octodecene:

ype 3 Pure Amount, gms. 252.5 252. 5 233.0 252. 5 252. 5 252.5 252. 5 252. 5 252. 5 A101 gins, 4 13. 3 13.3 12. 3 13. 3 13.3 13.3 13.3 13. 3 13.3 Conditions:

Reaction Temp. F- -59 55-59 28-32 55-59 55-59 55-59 55-59 55-59 55-59 Reaction Time, Min 70 42 70 70 70 70 70 70 Products:

after Wash, gms 382. 5 474. 3 477. 4 309. 0 415. 4 287. 0 376. 2 413.0 501.0 Sludge, gIns 12. 2 33.8 8. 4 29. 4 25. 7 29. 8 35. 0 30. 8 31. 0 Dist. of ProrL, gms:

700 F. 38. 0 128. 3 145. 4 72. 0 115. 0 60. 3 89. 7 122. 5 207. 0 700950' F 218. 5 306. 2 259. 7 211. 2 289. 3 185. 4 262. 4 278. 0 274. 0 950 F 126. 0 39. 8 72. 3 25.8 11. 1 41. 3 24.1 11.6 20. 0 Insp. of 700 F.+Prod.:

Vise. at 210 F., SSU 47. 4 40.9 43.1 39. (i 39. 0 38. 9 40.2 39. 6 41. 8 V. I 143 144 132 126 143 102 133 122 Pour Point, F +45 +30 +40 +40 +25 +35 +15 +35 +25 Insp. of 700-050 F. Prod;

Vise. at 210 F., SSU 40.4 40. 1 40.0 38. 4 39. 4 36. 6 39. 4 38. 7 40.5 V. I 139 137 143 116 121 120 91 127 115 Four Point, F +16 +11 +16 +20 0 +23 +2 +25 +14 1 s-Butyibenzene. 2 Kerosene Extract. 3 Oiefins purchased from Humphrey-Wilkinson, Inc., North Haven, Conn. 4 An H01 blanket was over the reaction mixture.

Table I4 MONOALKYLATION OF AROMAIICS Composition RIB. S/S T/T U/U V/V WfW XIX Y/Y Z/Z Reactants:

Aromatic Compound:

Type Korosen Extract s-Butyl oenzene Benzene Tetraiin Amount, gms 358. 0 358. 0 358. 0 358.0 268. 268 268. 4 156. 2 264. 4 1-Octadecenez Type Cracked I etrolatuln 4 Pure 5 Cracked Petroiatum 2 Pure Amount, gms 252. 5 252. 5 252. 5 252. 5 252. 5 252. 5 252.5 252. 5 252. 5 A101 gnisfi 13. 3 26. 6 13.3 13. 3 6. 6 26. 6 26. 6 26. 6 13.3 Conditions- Reaction Temp, F 55-59 55-59 55-59 86-90 55-59 55-59 55-59 55-59 55-59 Reaction Time, Min- 70 70 70 70 70 70 70 70 Products:

HO aiter Wash, gms 471. 5 404. 5 496. 0 501. 0 403. 0 383. 0 352. 5 239. 5 400. 0 Sludge. gms. 45. 0 77. 5 45. 0 48. 0 17. 0 80. 0 76. 8 97. 2 Dist. of Prod., gms.:

700 F 284. 0 218. 5 272. 0 266. 5 87. 0 172. 5 153. 5 123. 8 105. 0 700-950 F 162. 7 226. 8 204. 9 212. 9 283. 5 190. 3 174.4 75. 1 234. 3 950 F 24.8 19. 2 19. 1 21. 6 27. 5 20. 2 34. 6 40. 6 60. 7 Insp. of 700 F.+Prod.:

Vise. at 210 F., SSU 44. 5 43. 1 43.4 39. 6 40.4 41.1 42. 6 46. 0 47. 8 VI 98 92 105 91 129 111 121 117 111 Pour Point. F +5 -10 +10 +5 +20 +5 -5 +5 +40 Insp. of TOO-950 F. Prod;

Vise. at 210 F., SSU 42. 5 42.0 42. 8 38. 8 39. 4 39.9 40.0 30. 6 44. 5 VI 90 85 94 88 123 103 113 106 106 Pour Point, F -15 --20 6 5 +13 8 --15 7 +20 1 n-Butylbenzene.

2 Olefins purchased from Humphrey-Wilkinson, Inc., North Haven, Conn.

3 Contains 78% monoolefin s, 7% paraffins, 4% dioiefins, 11% aromatics.

4 An 1101 blanket was over the reaction mixture.

Compositions N/ N demonstrate that a monoalkylated benzene exhibits fair lubricating properties especially with respect to V1. The dialkylated compounds demonstrate the range f mat rials having different lubric ting properties which can be obtained. Composition F/F is an example of a material with an outstan n y W pou point. Composition A is an example of a material with an excellent V.I. but only an average pour point. Com position H is an example of a material with both a good V1, and a good pour point.

Compositions L/L, 0/0, and P/P are in the nature of comparative compositions. They demonstrate that the alkylated benzenes having relatively short chains, i.e., less than 4 carbon atoms and more than two alkyl substituents per benzene ring do not have the excellent all-around properties of the compositions of the invention.

EXAMPLE In The 750 to 950 P. fraction from the dialkylation of benzene with the C to C cracked wax olefins (composition F') was hydrogenated over a reduced Harshaw Chemical Co. nickel catalyst on kieselguhr at 400 F. and 1000 psi. until an almost theoretical uptake of hydrogen was observed. One weight percent of phenylanaphthylamine was added to the hydrogenated material obtained and to composition F. The material obtained nd o pos i F we e then ev u t w r pe t several conventional properties. The results obtained are summarized e ow in Ta le II.

Table II Composition I Hydrogenated Composition F Pour Point, F 75 75 Cloud Point, F 75 -75 Viscosity at 210 F., cs- 4. 680 5.850 Viscosity at 100" F., cs 26. 94 38. 52 V. I 98 102 Corirosifion and oxidatio I ability at 7 Corrosion, pig/cm! =l;0. 2 ;i:0. 2 Oxidation:

Viscosity change, percent 38 15 Total acid No 6.0 2. 0

*This test was carried out by immersing weight-ed strips of copper, ma gnesium, iron, aluminum and silver in 100 cc. of the sample which was maintained at 347 F. for 72 hours while bubbling 0.5 liters per hour of air through the sample. The metal strips are then reweighed to determine the weight change in mgJcn-ifl. The change in viscosity and the neutralization'number of the sample is also determined. None of the strips exhibited a weight change of more than :i=0.2 mg./em.-.

As can be seen from the above Table II, the change in viscosity of the hydrogenated material is very small compa ed w th th unhydrogenated mater al. There is also a considerable improvement in acid number.

What is claimed 1. A method for preparing dialkylated benzene compounds useful as lubricants which compounds have a Dean-Davis viscosity index of at least 90, a pour point of less than about +15 F. and boil from 700 to 950 P. which method comprises:

(I) allgylating a mono-alkyl substituted benzene nu cleus in a Friedel-Crafts reaction with an alpha olefin to form a para dialkyl substituted benzene nucleus I (a) wherein the first alkyl substituent on said para substituted benzene nucleus contains 4 to 15 carbon atoms and the second alkyl substituent 8 contains from 10 to 21 carbon atoms, said second alkyl substituent containing at least as manycarbon atoms as said first alkyl substituent,

(II) separating that portion of the reaction product boiling in the range of 700 to 950 F., said separated portion having a pour point of less than +15 F. and a Dean-Davis viscosity index of at least 90,

(III) hydrogenating said separated portion of said reaction product, and

(IV) recovering said dialkylated benzene compounds useful as lubricants.

2. A method according to claim 1 wherein the minimum number of carbon atoms in either substituent is 10 and there are from 3 to 8 more carbon atoms in one alkyl substituent than in the other.

3. The composition produced by the method of claim 2.

4. The composition produced by the method of claim 1.

5. A method for preparing vdialkylated benzene materials usefulas lubricating compositions, which materials have a Dean-Davis viscosity index of at least 90, a pour point of less than +15 F. and boil from 700 F. to 950 F., the method which comprises:

(a) alkylating a mono-alkyl substituted benzene nucleus in a Friedel-Cra fts reaction with a member selected from the group consisting of alpha olefins, hydroxylated paraffins and halogenated paraffins to form a reaction product containing a para substituted dialkyl benzene nucleus wherein the first alkyl substituent on said benzene nucleus contains 4 to 15 carbon atoms and the second alkyl substituent contains from 10 to 21 carbon atoms, said substituents each containing not less than 8 carbon atoms when said substituents have an equal number of carbon atoms, and the longer substituent having at least 3 more carbon atoms than the shorter substituent when said substituents are of unequal length and said shorter substituent contains less than 10 carbon atoms, said second alkyl substituent always being the longer substituent when said substituents are of unequal length, and

(b) separating and recovering that portion of the reaction product boiling between about 700-950 F., said separated portion comprising said para dialkyl substituted benzene nucleus and having a viscosity index of at least '90 and a pour point of less than +15 F. and hydrogenating said separated portion.

6. A method as defined in claim 5 wherein said selected member is an alpha olefin.

7. A method as defined in claim 5 wherein said Friedel- Crafts reaction is catalyzed with an aluminum chloride catalyst.

8. The composition produced by the method of claim 5.

9. The composition produced by the method of claim 6.

10. The composition produced by the method of claim :References Cited in the file of this patent UNITED STATES PATENTS 2,141,593 Clarkeet a1 Dec. 27, 1938 2,475,970 Lieber et al July 12, 1949 2,529,191 Rocchini et a1 Nov. 7, 1950 2,861,111 Scriabine et al; Nov. 18, 1958 2,887,518 Bloch et al. May 19, 1959 FOREIGN PATENTS 611,040 Great Britain Oct. 25, 1958 

1. A METHOD FOR PREPARING DIALKYLATED BENZENE COMPOUNDS USEFUL AS LUBRICANTS WHICH COMPOUNDS HAVE A DEAN-DAVIS VISCOSITY INDEX OF AT LEAST 90, A POUR POINT OF LESS THAN ABOUT +15*F. AND BOIL FROM 700 TO 950*F. WHICH METHOD COMPRISES: (I) ALKYLATING A MONO-ALKYL SUBSTITUTED BENZENE NUCLEUS IN A FRIEDEL-CRAFTS REACTION WITH AN ALPHA OLEFIN TO FORM A PARA DIALKYL SUBSTITUTED BENZENE NUCLEUS (A) WHEREIN THE FIRST ALKYL SUBSTITUENT ON SAID PARA SUBSTITUTED BENZENE NUCLEUS CONTAINS 4 TO 15 CARBON ATOMS AND THE SECOND ALKYL SUBSTITUENT CONTAINS FROM 10 TO 21 CARBON ATOMS, SAID SECOND ALKYL SUBSTITUENT CONTAINING AT LEAST AS MANY CARBON ATOMS AS SAID FIRST ALKYL SUBSTITUENT, (II) SEPARTING THAT PORTION OF THE REACTION PRODUCT BOILING IN THE RANGE OF 700 TO 950*F., SAID SEPARATED PORTION HAVING A POUR POINT OF LESS THAN +15*F. AND A DEAN-DAVIS VISCOSITY INDEX OF AT LEAST 90, (III) HYDROGENATING SAID SEPARATED PORTION OF SAID REACTION PRODUCT, AND (IV) RECOVERING SAID DIALKYLATED BENZENE COMPOUNDS USEFUL AS LUBRICANTS. 